do verification on forked blocks.

lib/bcoin/chain.js

@@ -980,7 +980,6 @@ Chain.prototype._onFlush = function _onFlush(callback) {
 
 Chain.prototype.add = function add(initial, peer, callback, force) {
   var self = this;
-  var host = peer ? peer.host : 'unknown';
   var total = 0;
 
   assert(!this.loading);
@@ -994,17 +993,13 @@ Chain.prototype.add = function add(initial, peer, callback, force) {
     var prevHash = block.prevBlock;
     var prevHeight, entry, checkpoint, prev, orphan;
 
-    // We already have this block. Do regular
+    // We already have this block.
-    // orphan resolution (won't do anything).
-    // NOTE: Wrap this in a nextTick to avoid
-    // a stack overflow if there are a lot of
-    // existing blocks.
     if (self.db.has(hash)) {
       self.emit('exists', block, {
         height: entry.height,
         hash: entry.hash
       }, peer);
-      return utils.nextTick(handleOrphans);
+      return done();
     }
 
     // Do not revalidate known invalid blocks.
@@ -1012,9 +1007,10 @@ Chain.prototype.add = function add(initial, peer, callback, force) {
       self.emit('invalid', block, {
         height: -1,
         hash: hash,
-        seen: true,
+        seen: !!self.invalid[hash],
-        chain: self.invalid[prevHash]
+        chain: !!self.invalid[prevHash]
       }, peer);
+      self.invalid[hash] = true;
       return done();
     }
 
@@ -1133,57 +1129,6 @@ Chain.prototype.add = function add(initial, peer, callback, force) {
       }
     }
 
-    // See if the entry already exists.
-    if (self.db.has(entry.height)) {
-      return self.db.getAsync(entry.height, function(err, existing) {
-        if (err)
-          return done(err);
-
-        // Shouldn't be the same by this point.
-        assert(existing.hash !== entry.hash);
-
-        // A valid block with an already existing
-        // height came in, that spells fork. We
-        // don't store by hash so we can't compare
-        // chainworks. We reset the chain, find a
-        // new peer, and wait to see who wins.
-        assert(self.db.getHeight(entry.hash) === -1);
-
-        // The tip has more chainwork, it is a
-        // higher height than the entry. This is
-        // not an alternate tip. Ignore it.
-        if (existing.chainwork.cmp(entry.chainwork) > 0)
-          return done();
-
-        // NOTE: We should do contextual verification
-        // here if we were a fullnode that actually
-        // stored multiple chains, but since we backoff,
-        // we can ignore that until the shorter chain
-        // stops being propogated.
-
-        // The block has equal chainwork (an
-        // alternate tip). Reset the chain, find
-        // a new peer, and wait to see who wins.
-        // self.revertHeight(existing.height - 1, function(err) {
-        self._revertLast(existing, function(err, existingBlock) {
-          if (err)
-            return done(err);
-
-          self.emit('fork', block, {
-            height: existing.height,
-            expected: existing.hash,
-            received: entry.hash,
-            checkpoint: false
-          }, peer);
-
-          return done();
-        }, true);
-      });
-    }
-
-    // Add entry if we do not have it.
-    assert(self.db.getHeight(entry.hash) === -1);
-
     // Lookup previous entry.
     // We can do this synchronously:
     // it is already cached.
@@ -1197,6 +1142,56 @@ Chain.prototype.add = function add(initial, peer, callback, force) {
       if (err)
         return done(err);
 
+      // Real fork resolution would just be this.
+      // if (entry.chainwork.cmp(self.tip.chainwork) > 0)
+      //   return self.setBestChain(entry);
+      // return done();
+
+      // See if the entry already exists.
+      if (self.db.has(entry.height)) {
+        return self.db.getAsync(entry.height, function(err, existing) {
+          if (err)
+            return done(err);
+
+          // Shouldn't be the same by this point.
+          assert(existing.hash !== entry.hash);
+
+          // A valid block with an already existing
+          // height came in, that spells fork. We
+          // don't store by hash so we can't compare
+          // chainworks. We reset the chain, find a
+          // new peer, and wait to see who wins.
+          assert(self.db.getHeight(entry.hash) === -1);
+
+          // The tip has more chainwork, it is a
+          // higher height than the entry. This is
+          // not an alternate tip. Ignore it.
+          if (existing.chainwork.cmp(entry.chainwork) > 0)
+            return done();
+
+          // The block has equal chainwork (an
+          // alternate tip). Reset the chain, find
+          // a new peer, and wait to see who wins.
+          // self.revertHeight(existing.height - 1, function(err) {
+          self._revertLast(existing, function(err, existingBlock) {
+            if (err)
+              return done(err);
+
+            self.emit('fork', block, {
+              height: existing.height,
+              expected: existing.hash,
+              received: entry.hash,
+              checkpoint: false
+            }, peer);
+
+            return done();
+          }, true);
+        });
+      }
+
+      // Add entry if we do not have it.
+      assert(self.db.getHeight(entry.hash) === -1);
+
       if (!verified) {
         self.invalid[entry.hash] = true;
         self.emit('invalid', block, {